Conventionally, the electromagnetic actuator includes a coil that generates a magnetic field upon energization. An inner stator is disposed inside the coil, and an eddy current is generated on a side of the inner stator close to the coil upon energization. A magnetic field is generated by the eddy current, which may cancel the magnetic field generated by the coil. As a result, the magnetic field by the eddy current may interfere with operation of the armature.
For example, Patent Literature (DE 10235240 A) discloses a method for suppressing occurrence of the eddy current. More specifically, Patent Literature discloses a slit extending along the axial direction over the entire region of the magnetic material. Thus, the magnetic material is entirely split by the slit. Since a current is shut off by the slit, occurrence of the eddy current may be suppressed.
As described above, the slit of Patent Literature, which completely splits the magnetic material, is formed only one. Therefore, it would be difficult to obtain sufficient effects of suppressing the eddy current from the single slit. If two or more slits are formed in the stator, the stator is split into a plurality of parts, which may additionally require a complex structure to hold the stator.
In view of the above, it is an objective of the present disclosure to provide an electromagnetic actuator that is capable of suppressing occurrence of an eddy current with a simple structure.